An acrylic fiber having an excellent color developing property, bulkiness, heat retaining property and soft feeling is a material used widely in a clothes field, accessory field, interior field, material field or the like, and it is developed mainly by staple. In contrast, cellulose acetate having an excellent glossiness, color developing property and dry feeling is regarded as a high quality clothes material, and it is developed mainly by tow and filament. However, since it does not have a fiber physical property durable for yarn spinning, it is not developed by staple.
Recently, development of a new material having a new feeling and functions, such as one having a deodorizing function and a moisture absorbing and retaining function in particular, is highly demanded, and as a method for developing techniques, there is polymer compositing. Complexing of a polymer is an effective method for reciprocating material characteristics of each other. Several reports have been provided on the polymer compositing technique of cellulose acetate and an acrylonitrile based polymer. As to the feeling, for example, a technique for compositing cellulose acetate and an acrylonitrile based polymer is disclosed in Japanese Patent Application Laid-Open (JP-A) Nos. 2-154713, and 3-234808. JP-A No. 2-154713 is for one having a feeling inherent to a conventional acetate fiber, and JP-A No. 3-234808 is for one having a feeling inherent to a conventional dry acrylic based fiber.
As to the deodorizing function, for example, JP-A No. 1-259867 discloses a technique for orienting a metal ion to an amide oximated fiber. However, according to the technique, since the fiber is colored by a hue inherent to the metal, a ;problem is involved in that an end use is limited. Furthermore, a technique for adding a silicate metal salt or an aminomo silicate metal salt to an acrylic based copolymer (JP-A Nos. 9-176917 and 9-291416) has been proposed. Since the technique requires a copolymer having acrylonitrile as a principal constituent unit and a non compatible polymer having miscibility in addition to an additive, a production process is complicated. Additionally, although a technique for containing a titanium oxide having a photo catalyst function in a fiber (JP-A No. 10-8327) has been proposed, it does not function effectively at a place whereat ultraviolet rays are weak.
Moreover, as to the moisture absorbing function, which is often applied by a post-process, washing resistance is poor. Therefore, a binder such as acrylic resin, an urethane resin and an epoxy resin is needed for improving durability, which deteriorates the feeling of the fiber itself, and thus it is problematic. Furthermore, a technique for compositing a moisture absorbing and discharging component in a synthetic fiber has been proposed. Although the technique (JP-A No. 11-279842) has both a moisture absorbing function and a moisture discharging function, no description is disclosed for a moisture retaining function thereof.
In order to solve the above-mentioned conventional problems, an object of the invention is to provide an acrylic based composite fiber having a new feeling different from that of a conventional cellulose acetate fiber, cellulose fiber and acrylic fiber, excellent fiber physical properties and process ability of yarn spinning, and excellent function properties, in particular, a deodorizing function and moisture absorbing and retaining function.